A-IMS aims to improve or fracture the IMS standard?

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A-IMS aims to improve or fracture the IMS standard?

Verizon, Cisco, Lucent Technologies, Motorola, Nortel and Qualcomm along with key telecom industry suppliers, today announced a vision for the advancement of next-generation network architecture for wireless mobile telecommunications networks. Their goal has been to develop enhancements to a well known, emerging architecture, known as IMS (IP Multi-media Subsystem). 

The multi-vendor team has generically termed this architecture A-IMS – for Advances to IMS -- in order to reflect its evolution from work done earlier in technology standards bodies.   The A-IMS architecture developed by the task force provides solutions to implement next-generation services in current networks, as well as creates a foundation for the efficient roll-out of both SIP- and non-SIP-based services in future networks. 

When I first heard about A-IMS and the taskforces "extensions" to the IMS standard, I couldn't help but be reminded of Microsoft making extensions to their browser that broke industry standards and fractured the browser market.  IMS is accepted as a core component of virtually all next-generation, IP-based communications networks for SIP-based applications, and is designed to assure standardization of multi-media services across all of these interconnected networks. So it is critical that any improvements made by the A-IMS initiative is rolled into the IMS standard.

I listened to the conference call and they claim that these "extensions" to the IMS standard will be put forth to the appropriate standards bodies. They pointed out that the response from the market has been positive and that the goal is not to cause a schism in the standard but instead to help bring more security, interoperability and stronger features.

Additionally, on the conference call Dick Lynch, Executive Vice President and CTO of Verizon Wireless pointed out that Verizon has been in discussion with other carriers and the goal is to make this a standard implemented wordwide and not just something for Verizon. He added that the years worth of work on enhancing IMS goal is to help move IMS forward.

Dick Lynch said, “We applaud the visionaries who have done a great job developing IMS over the last few years.  But as we approached implementation planning, it became apparent that there are some practical, real-world issues that need to be addressed if we are to transparently and completely deploy and maximize the use of this new architecture.  To us, it is also important that it be built to support the bridging of the present non-IP reality as we transition to the future.  As people look at what our task force has accomplished, I expect that they will see significant benefits, including embedding VoIP hooks into the lower levels of the stack and addressing security issues in a more systemic way.  These are exciting advancements that are headed rapidly into our mainstream technology roadmap.”

The current outputs of the task force are a concept document and an architecture document that are being provided to industry leaders.  From these documents, the task force companies plan to make necessary standards contributions in the immediate future. 

“The promise of IMS is extraordinary, for wireless service providers, as well as for all network providers.  A-IMS enhances the opportunity for success for not only the network providers but also for companies in technology, infrastructure, handset manufacturing and service design and, most importantly, for the consumer,” said Charlie Giancarlo, Chief Development Officer, Cisco. 

“Having been at the forefront of creating IMS-based next-generation multi-media solutions for mobile networks, we recognize the benefits of this collaboration, particularly in terms of multi-vendor interoperability, as we move into an all-IP mobility world,” said Paul Mankiewich, Chief Technology Officer, Lucent Technologies Network Systems Group.  “This effort continues to enable the delivery of blended voice, video, data and multi-media applications, what we call Blended Lifestyle services, to mobile end users.”

“This joint task force has defined the missing transition step from today to pure IP architecture, and knowledge learned from this effort will help us in development of seamless mobility solutions using this new architecture.  We see operators adopting A-IMS to deploy a unified platform for the rapid deployment of new services, including SIP-based interactive applications and non-SIP applications, all of which run on top of IP,” said Fred Wright, Senior Vice President, North America Region, Networks & Enterprise, Motorola.

“With our extensive experience deploying VoIP networks and SIP-based applications worldwide, we have a unique understanding of the system requirements and design and configuration enhancements necessary for successfully implementing VoIP in a wireless environment.  With the augmentations to the current standards we envision coming from A-IMS, wireless VoIP can efficiently arrive in the mainstream a lot sooner than anticipated,” predicted Richard Lowe, President, Mobility and Converged Core Networks, Nortel.

“With A-IMS, Qualcomm will be able to provide a consistent client environment that will drive the faster deployment of new and innovative IP-based applications,” said Roberto Padovani, Chief Technology Officer, Qualcomm.  “By deploying an access-agnostic A-IMS- based core network, operators will benefit from seamless integration of a rich array of services delivered across access technologies. A-IMS also provides operators flexibility in configuring and controlling services, and allows the device client to implement consistent policies for dealing with air interfaces, security, signaling and multi-media capabilities, while freeing the application developer to focus on providing compelling functionality to the user.”

The A-IMS standard is based on several key architectural principles, including:

Comprehensive Security: Security is more than authentication, and involves all components in the network, including the devices. Indeed, security agents run on the network devices, providing reverse-firewalls to protect the network from the device and to aid in posture assessment during logon. Comprehensive security also requires the Security Manager to monitor the network at all times, determine baseline traffic patterns, and then use those to detect and respond to anomalies. To respond, the Security Manager can change server configurations, install firewall rules or modify Intrusion Detection Services (IDS) behaviors.

Uniform Treatment of SIP and non-SIP Applications: To the greatest degree possible, A-IMS allows the service provider to manage and control both SIP and non-SIP applications in a uniform way. This is done primarily by usage of the Policy Manager (PM), which allows the service provider to manage the usage of network resources on behalf of both types of applications. Key network functions, including mobility, roaming and packet accounting are also defined in ways that allow them to support both types uniformly.
Dual Anchoring: A-IMS provides a mobile terminal with two IP addresses – one anchored in a Bearer Manager (BM) in the visited network, and one in a BM in the home network. Service provider policy controls which address is used for which applications. This allows for latency sensitive applications to use the visited anchor, whereas applications that require greater levels of service provider control can use the home anchor.

Three-Layer Peering: When connecting to roaming partners, peering occurs at three layers: security peering, used for access authentication, IP peering, used for transport of bearer traffic, and policy peering, used for control of bearer services. Policy server peering involves the usage of a policy server in both the home and visited networks. Usage of two allows for the home provider policies to apply even while roaming, yet allows them to be tempered by visited network policies on usage of the network.
Multi-Tiered Service Interaction Management: Feature interaction management across SIP-based applications, and between SIP and non-SIP applications is provided. Feature interaction management is linked with network policies, allowing for application interaction decisions to take into account the state of the network. The architecture also allows for extensibility to new interaction resolution mechanisms through the addition of service interaction application servers.

Highlights of the A-IMS plan clearly define several “pillars” as essential to the architecture:              

Bearer Manager (BM): Allocates resources and manages bearer traffic to meet customers’ service quality requirements. The primary functions include policy enforcement, mobility management, security, accounting, and access control.

Policy Manager (PM): A primary policy decision point for network policies, deciding the ways that the underlying network supports applications on behalf of subscribers and visitors to the network.
Application Manager (AM): The SIP services platform in the network that authorizes access to SIP services, provides SIP registration and authentication functions, and is responsible for the invocation and management of SIP-based features.
Security Manager (SM): Responsible for monitoring the network for security threats and responding to them in real time, making decisions on what devices are allowed access to the network based on their posture – a measure of the safety of the device based on the freshness of its software patches and security features.

Services Data Manager (SDM): The main repository of subscriber and network control data and collects and stores charging data for the network.

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